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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/x86/kernel/cpu/intel_pconfig.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/cpu/intel_pconfig.c')
-rw-r--r--arch/x86/kernel/cpu/intel_pconfig.c82
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel_pconfig.c b/arch/x86/kernel/cpu/intel_pconfig.c
new file mode 100644
index 0000000000..0771a905b2
--- /dev/null
+++ b/arch/x86/kernel/cpu/intel_pconfig.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel PCONFIG instruction support.
+ *
+ * Copyright (C) 2017 Intel Corporation
+ *
+ * Author:
+ * Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
+ */
+
+#include <asm/cpufeature.h>
+#include <asm/intel_pconfig.h>
+
+#define PCONFIG_CPUID 0x1b
+
+#define PCONFIG_CPUID_SUBLEAF_MASK ((1 << 12) - 1)
+
+/* Subleaf type (EAX) for PCONFIG CPUID leaf (0x1B) */
+enum {
+ PCONFIG_CPUID_SUBLEAF_INVALID = 0,
+ PCONFIG_CPUID_SUBLEAF_TARGETID = 1,
+};
+
+/* Bitmask of supported targets */
+static u64 targets_supported __read_mostly;
+
+int pconfig_target_supported(enum pconfig_target target)
+{
+ /*
+ * We would need to re-think the implementation once we get > 64
+ * PCONFIG targets. Spec allows up to 2^32 targets.
+ */
+ BUILD_BUG_ON(PCONFIG_TARGET_NR >= 64);
+
+ if (WARN_ON_ONCE(target >= 64))
+ return 0;
+ return targets_supported & (1ULL << target);
+}
+
+static int __init intel_pconfig_init(void)
+{
+ int subleaf;
+
+ if (!boot_cpu_has(X86_FEATURE_PCONFIG))
+ return 0;
+
+ /*
+ * Scan subleafs of PCONFIG CPUID leaf.
+ *
+ * Subleafs of the same type need not to be consecutive.
+ *
+ * Stop on the first invalid subleaf type. All subleafs after the first
+ * invalid are invalid too.
+ */
+ for (subleaf = 0; subleaf < INT_MAX; subleaf++) {
+ struct cpuid_regs regs;
+
+ cpuid_count(PCONFIG_CPUID, subleaf,
+ &regs.eax, &regs.ebx, &regs.ecx, &regs.edx);
+
+ switch (regs.eax & PCONFIG_CPUID_SUBLEAF_MASK) {
+ case PCONFIG_CPUID_SUBLEAF_INVALID:
+ /* Stop on the first invalid subleaf */
+ goto out;
+ case PCONFIG_CPUID_SUBLEAF_TARGETID:
+ /* Mark supported PCONFIG targets */
+ if (regs.ebx < 64)
+ targets_supported |= (1ULL << regs.ebx);
+ if (regs.ecx < 64)
+ targets_supported |= (1ULL << regs.ecx);
+ if (regs.edx < 64)
+ targets_supported |= (1ULL << regs.edx);
+ break;
+ default:
+ /* Unknown CPUID.PCONFIG subleaf: ignore */
+ break;
+ }
+ }
+out:
+ return 0;
+}
+arch_initcall(intel_pconfig_init);